- Carbonylative Transformation of Allylarenes with CO Surrogates: Tunable Synthesis of 4-Arylbutanoic Acids, 2-Arylbutanoic Acids, and 4-Arylbutanals
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In this Communication, procedures for the selective synthesis of 4-arylbutanoic acids, 2-arylbutanoic acids, and 4-arylbutanals from the same allylbenzenes have been developed. With formic acid or TFBen as the CO surrogate, reactions proceed selectively and effectively under carbon monoxide gas-free conditions.
- Wu, Fu-Peng,Li, Da,Peng, Jin-Bao,Wu, Xiao-Feng
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p. 5699 - 5703
(2019/08/01)
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- Synthetic applications of o- and p-halobenzyl sulfones as zwitterionic synthons: Preparation of Ortho-substituted cinnamates and biarylacetic acids
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The synthetic applications of o-halobenzyl and p-halobenzyl sulfones as precursors of 1,3- and 1,5-zwitterionic synthons, respectively, are described. Their α-sulfonyl carbanions, generated by means of the phosphazene base P2-Et or BuLi or K2CO3 under PTC conditions, reacted with different electrophiles such as alkyl halides, aldehydes, and electrophilic olefins. Palladium-catalyzed cross-coupling processes such as Heck, Suzuki, and Sonogashira reactions can be efficiently performed at the halogen atom. These two sequential functionalization processes are applied to the synthesis of ortho-substituted cinnamates and pharmaceuticals belonging to the family of p-biarylacetic acids such as 4-biphenylacetic acid, namoxyrate, xenyhexenic acid, and biphenylpropionic acid.
- Costa, Ana,Najera, Carmen,Sansano, Jose M.
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p. 5216 - 5225
(2007/10/03)
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- Hydroxamic acid compounds as metalloprotease and TNF inhibitors
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The present invention provides novel hydroxamic acids and carbocyclic acids and derivatives thereof and to pharmaceutical compositions and methods of use of these novel compounds for the inhibition of matrixmetalloproteinases, such as stromelysin and other matrix metalloproteinases, and also inhibit the production of tumor necrosis factor (TNF), and are therefore useful for the treatment of arthritis and other related inflammatory diseases. These novel compounds are represented by Formula I below: STR1
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- Process for preparing esters of arylacetic acids from alpha-halo-alkylarylketones
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Esters of arylacetic acids, more particularly lower alcohol esters of arylacetic acids, including those substituted on the methylene group, are prepared by rearrangement of the corresponding alpha-halo-alkylarylketones with Ag compounds in lower alcohols and in an acid medium. From the alkyl esters so prepared, their respective free acids can be obtained, if desired, by various means such as hydrolysis or the shift with mineral acids of the alkaline salts prepared by reaction with alkali, etc.
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- Carbanions. 21. Reactions of 2- and 3-p-Biphenylylalkyl Chlorides with Alkali Metals. Preparation of Labile Spiro Anions
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The present work was undertaken to see if (3-p-biphenylylpropyl)- and (2-p-biphenylethyl)cesium cyclize like (4-p-biphenylbutyl)cesium to stable spiro anions.Reaction of 1-p-biphenylyl-3-chloropropane (5) with Cs-K-Na alloy in THF at -75 deg C gave, under the optimum conditions found, 36percent of 7-phenylspironona-6,5-dien-5-yl anion (8) besides 3-p-biphenylylpropyl (7), 1-p-biphenylylpropyl (9), and p-biphenylylmethyl (10) anions, according to the products of carbonation.The spiro anion 8 (Cs+ as the counterion) has a half-life of about 13 min at -75 deg C.Incontrast, 5 reacts with lithium to give predominantly (3-p-biphenylylpropyl)lithium.Reaction of 1-p-biphenylyl-2-chloroethane with Cs-K-Na alloy gave no appreciable spiro anion under conditions which were successful with 5.In the reaction of 1-p-biphenylyl-2-chloro-2-methylpropane (28) with Cs-K-Na alloy the α-gem-dimethyl group accelerates migration of the p-biphenylyl group to give products similar to those from 2-p-biphenylyl-1-chloro-2-methylpropane (24); however, the expected intermediate spiro anion 26 was undetectable by the carbonation technique.With both α- and β-gem-dimethyl groups, 2-p-biphenylyl-3-chloro-2,3-dimethylbutane (41) reacts with Cs-K-Na alloy to give 1,1,2,2-tetramethyl-6-phenylspiroocta-5,7-dien-4-yl anion (43) and 2-p-biphenylyl-1,1,2-trimethylpropyl anion (42) in about a 2:1 ratio according to the results of carbonation.The open anion 42 and the spiro anion 43 appear to be in mobile equilibrium (Cs+ as the counterion) with half-lives of about 22 min in THF at -75 deg C.With lithium as counterion, only the open product (2-p-biphenylyl-1,1,2-trimethylpropyl)lithium (50) was detectable by carbonation.
- Grovenstein, Erling,Lu, Pang-Chia
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p. 2928 - 2939
(2007/10/02)
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- SILVER ASSISTED REARRANGEMENT OF PRIMARY AND SECONDARY α-BROMO-ALKYLARYLKETONES
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The silver assisted rearrangement of primary and secondary α-bromo-alkylarylketones is reported for the first time.The influence of the acidity on the reaction selectivity is discussed.
- Giordano, Claudio,Castaldi, Graziano,Casagrande, Francesco,Abis, Luigi
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p. 1385 - 1386
(2007/10/02)
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